The conventional type of carburetor customarily utilized in internal combustion engines includes a butterfly valve or valves actuable by an accelerator pedal to control the flow of air through the carburetor to an intake manifold, with fuel being drawn into the flow of air by suction to form a combustible mixture. Various accessory devices have been added to this basic type of carburetor over the years in an attempt to alter or refine its operation and improve the characteristics of the burnable mixture delivered to the engine, and to compensate for changes in operating conditions such as acceleration, increased load, etc. As a result, carburetors have become very complex intricate mechanisms having a large number of parts containing and defining many critically interrelated flow passages and metering ports and requiring frequent tune-up or repair for satisfactory operation. Further, in spite of this complexity, conventional carburetors do not control and regulate the air-fuel mixture satisfactorily under different operating conditions, and do not vaporize and disperse the fuel as effectively as would be desired. For example, upon acceleration the conventional carburetor injects an essentially unmeasured quantity of fuel into the air stream in a manner not even approximating a proper air-fuel ratio. Other similarly imprecise expedients are employed to meet various other requirements of the engine, with the overall result that very low mileage per gallon of fuel is attained. In addition, improper combustion of the poorly mixed and poorly proportioned fuel and air mixture tends to cause emission by the engine of unburned gases and other pollutants requiring addition of emission control devices to the engine in order to meet antipollution standards set by the Government.